A number of portable, low pressure vacuum apparatuses capable of producing vacuum pressures down to about 500 mm HG currently exist. Medicine, particularly the wound healing arts, is a field where such devices have a specific utility. In the wound healing arts, it has been recognized that the removal of excess fluid from a wound site can improve the healing of the wound. This recognition has motivated the field to develop wound treatment regimens that include the use of vacuum devices for removing excess exudate from a wound site. For example, in full thickness dermal wounds devices to assist in the removal of excess fluid from these wounds have been developed and used. Further, because of the recognized benefits of encouraging patients to be active and mobile if possible, these devices need to be portable, and preferably, personally portable.
One strategy for providing a personally portable, low pressure vacuum source for drainage of wound site involves the use of a passive vacuum reservoir. Examples of this types of device includes those disclosed by Fell, U.S. Pat. No. 5,073,172; Seddon et al., U.S. Pat. No. 6,024,7311 and Dixon et al., U.S. Pat. No. 5,944,703. Typically, these devices comprise an evacuated cannister attached to a drainage tube. Because the vacuum pressure in the reservoir of these devices continuously decreases as the wound is drained (and the reservoir filled), they often include a means for regulating the pressure delivered to the wound site at some level below the maximum pressure of the vacuum reservoir. Additionally, these devices require a reservoir of a relatively larger volume than that of the volume of fluid they are capable of removing from a wound site.
Recognizing these limitations, the field has been further motivated to develop means for providing a portable, low pressure vacuum source for drainage of a user's wound site which provides a relatively constant vacuum pressure. A strategy for accomplishing this objective includes having the device comprise a vacuum pump to provide a constant low pressure vacuum source, or to replenish a separate vacuum reservoir. An example of this type of device includes that disclosed by McNeil et al., U.S. Pat. No. 4,710,165. Also see U.S. Pat. No. 5,134,994 to Say. Although portable, these devices are bulky and obvious to an observer of the user, and may subject the user to embarrassment or personal questions. It would be beneficial to have a portable vacuum device that was personally portable by the user without being obvious to an observer.
An apparatus which addresses this latter benefit is disclosed in U.S. Pat. No. 6,142,892 to Hunt et al. The Hunt apparatus is supported on a belt or harness worn by the user, and is small enough to be unobtrusive when worn under a jacket or the like. However, the Hunt apparatus utilizes a liquid reservoir containing the fluids drained from a wound site. Fluids contained in the liquid reservoir of Hunt are subject to slouching, which may adversely affect the function of the Hunt apparatus if the fluid prematurely enters an inappropriate pathway (the outlet end of the cannister). Also, the Hunt device requires multiple tubes or a multi-lumen tube running from the device to the wound site to accomplish its full utility. Additionally, the Hunt apparatus is intended to be worn by a patient at waist level or higher. This means that wound sites below and distal to the users waist can be subjected to a higher vacuum pressure than with a device that may be located more proximal the wound site than the Hunt apparatus.
Although the above apparatuses may be useful in the field for accomplishing their intended purposes, it would be beneficial to have an alternative personally portable vacuum device that can be worn unobtrusively by the user, and which is not subject to slouching of the fluid it retains, and further which does not require special tubing to connect it to a wound site.